1. Field of the Invention
The present invention relates to an apparatus for conveying a liquid crystal display panel. More particularly, the present invention relates to an apparatus for conveying various sizes of unit liquid crystal display panels.
2. Discussion of the Related Art
A liquid crystal display device supplies liquid crystal cells with data signals according to image information, respectively, in order to display the desired image. The liquid crystal cells are arranged in a matrix like configuration and the image is displayed by controlling a light-transmittance of each liquid crystal cells.
A cutting process is performed on the liquid crystal displays, cutting the displays into a unit liquid crystal display panels. Generally, the process includes a scribing process by forming a scribing line on a substrate of a mother substrate with a pen having hardness greater than that of glass. Additionally, the process includes propagating a crack along the scribing line. Such a cutting process of the unit panels is explained in detail by referring to the attached drawings as follows.
FIG. 1 illustrates a cross-sectional view of a first mother substrate having thin film transistor array substrates and a second mother substrate having color filter substrates. The first and second mother substrates are bonded to each other, thereby forming a plurality of liquid crystal display panels.
Referring to FIG. 1, the unit LCD display of the mother substrate 20 has a unit thin film transistor array substrate 1. One side of the thin film transistor array substrate 1 protrudes longer than the corresponding side of the color filter substrate 2. The gate and data pad parts (not shown in the drawing) are formed at the corresponding edges of the thin film transistor array of substrates 1 and do not overlap with the color filter substrates 2.
The color filter substrates 2 on the second mother substrate 30, are spaced apart from each other with a dummy area 31. The dummy area 31 corresponds to the protruding area of each of the thin film transistor array on the first mother substrate 20.
Moreover, the unit liquid crystal display panels are arranged to make best use of the first and second mother substrates 20 and 30. The unit liquid crystal display panels differ from each other according to the various models. The unit liquid crystal display panels are generally formed to separate from each other at the dummy area 32.
After the first and second mother substrates have been bonded together the liquid crystal display panels are individually cut. Simultaneously, the dummy area 31 of each of the color filter substrates 2 and the other dummy area 32 separating the unit liquid crystal display panels from each other are removed.
FIG. 2 illustrates a schematic layout of an individually cut unit liquid crystal display panel according to the related art.
Referring to FIG. 2, an individual unit liquid crystal display panel 10 includes an image display part 13 having liquid crystal cells arranged in a matrix form. A gate pad part 14 connects gate lines GL1–GLm of the image display part 13 to a gate driver integrated circuit (not shown in the drawing) for supplying gate signals. The data pad part 15 connects data lines DL1–DLn of the image display part 13 to a data driver integrated circuit (not shown in the drawing) for supplying image information. The gate pad parts 14 and data pad parts 15 are arranged on the edge of the thin film transistor array of substrate 1.
Thin film transistors are formed at areas where the data lines and gate lines cross each other on substrate 1. The thin film transistors switch the liquid crystal cells and pixel electrodes are connected to the thin film transistors for supplying electric fields to the corresponding liquid crystal cells. A passivation layer is formed on an entire surface to protect the data lines DL1–DLn, gate lines GL1–GLm, thin film transistors, and electrodes.
Color filters are formed on substrate 2. The color filters are separated from an adjacent cell area through a black matrix and a common electrode. The common electrode is a counter electrode of the pixel electrodes on the thin film transistor array substrate 1.
A cell gap is provided for leaving a predetermined interval between the substrates 1 and 2. Substrates 1 and 2 are bonded to each other by a sealing part (not shown in the drawing) that is formed on a periphery of the image display part 13. A liquid crystal layer (not shown in the drawing) is formed in a separating space between substrates 1 and 2.
Additionally, a short circuit line (not shown in the drawing) is formed on an edge of the thin film transistor array of substrate 1. The short circuit line prevents static electricity generated during the patterning of conductive layers from damaging the thin film transistor array of substrate 1. The short circuit line is typically removed after the liquid crystal display panels are cut into individual unit liquid crystal display panels.
For example, after the liquid crystal display panels have been cut into individual unit liquid crystal display panels the edges of the individual unit liquid crystal display panels are grinded to remove the short circuit line. Additionally, the edges are grinded in order to prevent damage from external impact and prevent injury from any sharp edges of the unit liquid crystal display panels that may be present.
Finally, a final testing analysis is performed to determine normal operation of the individual unit liquid crystal display panels. The panels are judged with varying criteria, for example, a ‘good product.’
As mentioned in the foregoing explanation, the grinding and checking processes are carried out after the process of cutting the liquid crystal display panels into the individual unit liquid crystal display panels. A conveying apparatus precisely controls this process by transporting the corresponding unit liquid crystal display panel to the desired location. Additionally, the movement via the apparatus is utilized to minimize impact on the panel. An apparatus for conveying the liquid crystal display panel is explained in detail by referring to the attached drawings as follows.
FIG. 3 illustrates a close up view of an apparatus for conveying an individual liquid crystal display panel according to the related art.
Referring to FIG. 3, the apparatus includes a cylinder 53 for driving a pair of pistons 51 and 52 with an air in a back and forth direction. A vertical driving unit 55 for driving the cylinder 53 capable of moving along a conveying shaft 54. A pair of support shafts 56 and 57 connected to pistons 51 and 52. The support shafts protrude on lateral sides of the cylinder 53. A pair of robot arms 58 and 59, each of the arms has on of their ends connected to the support shafts 56 and 57. The robot arms extend in a direction substantially perpendicular to the support shafts 56 and 57. A pair of clamping units 60 and 61 connected to lower portions the ends of the robot arms 58 and 59. The robot arms are separated at a predetermined distance, thereby forming a separating area.
FIGS. 4A to 4D illustrate close up views of an apparatus for conveying an individual unit of a liquid crystal display panel according to the related art.
Referring to FIG. 4A, the cylinder 53 is driven via air injection and discharge, thereby the pistons 51 and 52 move back and forth. Accordingly, the pair of the robot arms 58 and 59 are moved back and forth as the pistons move back and forth. The robot arms can be moved at predetermined intervals from both sides for loading an individual unit liquid crystal display panel 10 on a first table 62. In this case, both of the sides of the loaded unit liquid crystal display panel 10 protrude out of the first table 62.
Referring to FIG. 4B, the vertical driving unit 55 lowers the cylinder 53. The pair of robot arms 58 and 59 are lowered to a level smaller than or at least equal to the level of the individual unit of liquid crystal display panel 10.
Referring to FIG. 4C, the cylinder 53 is driven in a direction of the arrows making the pair of the pistons 51 and 52 get closer to each other through the injection and discharge of air. Accordingly, the pair of the robot arms 58 and 59 are driven in the direction making the robot arms 58 and 59 get closer to each other and are arranged closely to both of the sides of the unit of liquid crystal display panel 10 on the first table 62.
Referring to FIG. 4D, the vertical driving unit 55 elevates the cylinder 53 in the direction of the arrow. Accordingly, the pair of the robot arms 58 and 59 are lifted, thereby elevating the liquid crystal display panel 10 supported by the clamping units 60 and 61.
As mentioned in the above explanation, once the liquid crystal display panel 10 is lifted together with the robot arms 58 and 59 the vertical driving unit 55 is driven to move along the conveying shaft 54. Accordingly, the liquid crystal display panel 10 is transported to the desired location.
Once the liquid crystal display panel 10 has been conveyed to the desired location, it is put down on another table in a reverse manner as explained in FIGS. 4A to 4D, above.
However, the above-explained apparatus according to the related art requires that the robot arms correspond to the size of the liquid crystal display panel that is to be moved. Accordingly, if the size of the liquid crystal display panel to be conveyed is changed the robots arm must be changed. Therefore, the related art apparatus reduces the efficiency of the operation by delaying the process time and thereby reduces the overall productivity.
Additionally, a plurality of robot arms should be prepared to cope with the sizes of the different liquid crystal display panels, thereby the investment cost is increased and additional space for keeping a plurality of the robot arms is required.